Abstract

In recent years interest in the cell population kinetics of gastrointestinal mucosa has been stimu-lated by several factors. One is the realization that the turnover rates of mucosal cell populations are among the most rapid in the body (1). Another is the possibility that abnormal histologic appear-ance of mucosal epithelial cells in certain disease states (for example ulcerative colitis, peptic ulcer disease) in humans may be related to impaired differentiation or proliferation of these elements (2-4). The micro-radioautographic methods of measur-ing cell proliferation and migration that are now available should prove useful in the analysis of the renewal of human mucosal tissues (1, 5). These techniques have been used in several studies to measure epithelial cell regeneration in animals, in-cluding studies of population kinetics in the small intestine of mice (6, 7). In the work reported here, similar methods were used to measure rates of epithelial cell proliferation and migration in mouse colon. Estimates were made from the data of the duration of the proliferative cycle and its various portions, and of the speed of migration of the epithelial cells. MATERIAL AND METHODS Thirty-five adult C57 Brown male mice were used. The animals were labeled by intraperitoneal injection of tritiated thymidine (0.7,uc per g of animal, specific activity 360 cpm, dissolved in 1 ml saline); 25 were sacrificed be-tween 0.5 and 40 hours and 10 were killed 1 week after inj ection. Specimens of ascending and sigmoid colon were removed, fixed in neutral formol-saline, embedded in paraffin, and sectioned at 5,u. Slides were dipped into NTB (Kodak) liquid emulsion, exposed for 2 to 4 weeks, *This work was aided by grants from The John A.